16 SEXUAL SELECTION. [Part II. 



pardonable exaggeration, as formed of polished scales of 

 gold encrusting lapis-lazuli, rubies, sapphires, emeralds, 

 and amethysts, we may, with much probability, accept 

 this belief; for we have seen that the sexes in at least one 

 species differ greatly in color. With some fishes, as with 

 many of the lowest animals, splendid colors may be the 

 direct result of the nature of their tissues, and of the sur- 

 rounding conditions, without any aid from selection. The 

 gold-fish ( Cyprinus auratus), judging from the analogy 

 of the golden variety of the common carp, is, perhaps, a 

 case in point, as it may owe its splendid colors to a single 

 abrupt variation, due to the conditions to which this fish 

 has been subjected under confinement. It is, however, 

 more probable that these colors have been intensified 

 through artificial selection, as this species has been care- 

 fully bred in China from a remote period. 26 Under nat- 

 ural conditions it does not seem probable that beings so 

 highly organized as fishes, and which live under such com- 

 plex relations, should become brilliantly colored without 

 suffering some evil, or receiving some benefit, from so 

 great a change, and consequently without the intervention 

 of natural selection. 



What, then, must we conclude in regard to the many 

 fishes, both sexes of which are splendidly colored ? Mr. 

 Wallace 27 believes that the species which frequent reefs, 



26 Owing to some remarks on this subject, made in my work ' On the 

 Variation of Animals under Domestication,' Mr. W. F. Mayers (' Chinese 

 Notes and Queries,' Aug. 1868, p. 123) has searched the ancient Chinese 

 encyclopaedias. He finds that gold-fish were first reared in confinement 

 during the Sung Dynasty, which commenced a. d. 960. In the year 1129 

 these fishes abounded. In another place it is said that since the year 

 1548 there has been "produced at Hang-Chow a variety called the fire- 

 fish, from its intensely red color. It is universally admired, and there is 

 not a household where it is not cultivated, in rivalry as to its color, and 

 as a source of profit." 



97 'Westminster Review,' July, 1867, p. 7. 



